Question

SELECT t.title, Max(t.st) 
FROM (SELECT title, 
               Avg(stars) AS st 
        FROM movie 
               JOIN rating USING(mid) 
        GROUP BY title)t;

这是我正在编写的查询，用于获取AVG(stars)的最大值及其对应的标题。最高价值很好，但标题出现问题。我没有相应的标题。

子查询的输出为：

Avatar                  4.0
E.T.                    2.5
Gone with the Wind      3.0
Raiders of the Lost Ark 3.33333333333
Snow White              4.5
The Sound of Music      2.5

整个查询的输出错误。

The Sound of Music 4.5

预期/正确的输出是

SnowWhite 4.5

Answer 1

尝试一下

select t.title,
       t.st
  from 
(select title,
        avg(stars) as st,rank() over(order by avg(stars) desc) as rSt
   from movie 
   join rating using(mID)
  group by title)t where t.rSt=1  ;

首先按降序对电影进行排名，然后在外部查询的条件下，选择具有最高排名的电影。希望这会有所帮助：-）

Answer 2

您可以尝试使用相关子查询

select *
from 
(select title,
        avg(stars) as st
   from movie  a
   join rating b on a.mID=b.mID
  group by title
)t where st in
  (select max(st) from (select title,
        avg(stars) as st
   from movie  a
   join rating b on a.mID=b.mID
   group by title
  )t1 on t.title=t1.title)

Answer 3

您可以在查询中使用WHERE条件。您可以尝试联接，也可以只使用子查询。

Select title, max(stars) 
from table 
where stars = (select max(stars) from table)

或

SELECT top 1 title
FROM table
ORDER BY Stars DESC

SQL查询没有得到相应的列

3 个答案: